


Time Evolution Pill

by PaperFox19



Category: Katekyou Hitman Reborn!
Genre: Anal Sex, M/M, Macro/Micro, Oral Sex, Size Difference, Size Manipulation, Yaoi
Language: English
Status: Completed
Published: 2020-04-03
Updated: 2020-04-03
Packaged: 2021-02-28 22:47:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,421
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23455012
Author URL: https://archiveofourown.org/users/PaperFox19/pseuds/PaperFox19
Summary: Reborn asks Fuuta to try a new pill, it has some surprising results in more ways than one. Tier 3
Relationships: Futa/Sawada Tsunayoshi
Kudos: 20





	Time Evolution Pill

**Author's Note:**

> Please Read and Review

Time Evolution Pill

Reborn asks Fuuta to try a new pill, it has some surprising results in more ways than one. Tier 3

-x-

Fuuta had the power of ranking, capable of communicating with the Ranking Planet. He took requests even some of the weirder ones. Tsuna was so embarrassed when Reborn asked for the rankings of cock sizes in the vongola group.

He obeyed, much to Tsuna’s embarrassment. Tsuna was reserved about his size, and not in the traditional way. His bullies messed with him about anything and everything. So as Fuuta scanned the universe to learn the answer, Tsuna was sweating.

Fuuta began to write the results down. Fuuta was the smallest at 5 inches, Lambo beat him at 6, Mukuro beat him at 7, Ryohei was at 7.5, Gokudera and Yamamoto were tied at 8, Hibari was 9, and Tsuna was at the top of the charts with 10. “Fufu, so there is one part of you that is above average Tsuna.”

“Reborn, stop asking Fuuta to rank such things.” Fuuta was staring at his list. Blushing as he stared at Tsuna’s size. “Fuuta?”

“Huh, oh no I don’t mind. But I do have to get going,” he hugged Tsuna. “Later Big Brother.” he says before dashing off. ‘I can’t believe I’m the smallest.’ he thought sadly. ‘Big bro will only see me as a child.’

‘Hmm, there might be a way to fix things.’ He needed Tsuna to be proud so he came up with a plan. They had been working on a brand new set of pills. With how useful the dying will pills were, funding was given to explore other ventures.

One of the recent ones, was exactly what Reborn was needing. He took them and found Fuuta in his room. “Still thinking about Tsuna?” Fuuta gasped as Reborn came out of one of his many secret entrances. “Reborn!”

The assassin smirked and tossed Fuuta the pills. “Here give these a try.” he says. “Dying will pills?” he asked looking at them, but no they were a different size and color. “Trust me, these are special, if you do I can guarantee Tsuna won’t see you as a child.”

Fuuta stares at them, before opening the top and taking one of the pills. He popped it into his mouth and swallowed it. He felt a wave of heat wash through his body. His skin lit up. “Reborn what are these?” he gasped.

“Time Evolution Pills!” Before Fuuta could ask what they were, his body reacted. He was growing, and growing, and growing, his clothing getting tighter. His clothing could no longer contain his growing and aging body and began to rip.

Rip Rip Rip

Fuuta gasped, his feet ripping out of his socks. His pants ripped off along with his shirt. He was being aged 10 years, his baby fat melted away for lean muscle. The only thing not in tatters was his underwear, and thank you elastic. 

He grew tall, lean muscle, strong shoulders, long arms and legs, big feet. As he crossed into his puberty years, his cock and balls began to grow. “Ohhh!” he cupped his crotch. His 5 incher began to grow, and started rubbing against the confines of his underwear. “Mmmhhhmmm!”

The friction made his dick harden, which made his growing cock push against the fabric harder. The bulge in his tightywhities got bigger and thicker. His penis continued rubbing against his confines making Fuuta moan.

Not just the front, his ass grew plumper. His poor underwear wasn’t able to hand the growth on both ends. His cock had all but doubled in size and was still growing. ‘I’m as big as Big Brother!’ he thinks, rubbing the 10 incher in his undies.

His cock continued to grow and his balls seemed to swell with years of pent up seed. “It’s tight!” Fuuta moaned desperate. RIIIIIP “Ahhhh!” His 15 incher tore through the undies. The garment joining the tatters with the rest of his clothes.

The last years came and Fuuta was in his 10 Years Later self body. His cock sprang up slapping his stomach with a smack. “Ohhh!” his dick made it to 17 inches. “So big!” he gasped, hands coming to caress his new size.

His cock was sensitive after the change. A few simple touches and he started leaking pre. “Ohh yeah!” taking his hefty length in both hands he pumped himself. Hands gliding the long hard length, he couldn’t believe he was bigger than Tsuna.

He caressed the sensitive head, spreading pre around the head. Using the essence he coated his length and sped up his pumps. He gripped himself harder and worked that giant monster. “Oh oh oh oh oh, Tsuna-ni!” he moaned, his hefty balls lurched and his mountain of a cock turned into a volcano and his semen shot up and splattered the floor and his wall.

It was a massive stream for a few minutes, before it calmed down and thick ropes of cum shot from his length. Fuuta had his first orgasm, and his heart was racing. “Oh man!” his skin was flushed, his toes curled in orgasm. Despite the powerful release, he was still hard.

“Your a man now Fuuta. I’m sure Tsuna will be impressed.” Fuuta’s eyes lit up. “You are right, thank you Reborn!” he took the pills and scampered out of the room, hard cock swaying and bouncing as he moved.

-x-

Tsuna was laying in his bed. “Man why does Reborn do this stuff to me?” he thought. He was used to people bursting into his room, giving his life now. The last thing he was expecting was for 10 Years Later Fuuta to burst in, bare ass naked, rock hard, pre weeping from the tip. “Big Bro!” Fuuta called.

“Fuuta?!” he gasped. His cheeks burned as the naked male entered his room, cock bouncing like an excited puppy. The male grinned. He had met Fuuta in the future and it was strange seeing him again. “Did you get hit with the 10 Year Bazooka?”

“Now it’s all me, Big Bro!” he says, he shows Tsuna the pills. “Reborn gave me these.” Tsuna face palmed. “Of course he did.” he peeked and saw that man cannon pointed right at him. “Uh shouldn’t you put something on?”

“No, I’m really excited,” he grinned. “Look how big I am!” he says and strokes his mighty length. “I was hoping to be able to please you.” his hand came to rest on the bulge. Tsuna had gotten hard seeing the naked male. Fuuta palmed the confined arousal and Tsuna moaned.

He acted fast, undoing the smaller male’s pants and yanking them down, along with his boxers. “I now know why you always wore boxers Tsuna-ni.” Tsuna’s hefty cock sprang up, long and thick.

Fuuta laid kisses along his shaft, from the tip down his shaft, and kissed his balls. He trailed his tongue up, once at the tip he swirled his wet muscle around the sensitive head. “Ohhh!” Tsuna moaned.

All rational thought fell out of his head as Fuuta wrapped his lips around the tip and started sucking. ‘So good!’ Fuuta thought. He descended taking inch after glorious inch. He’d never sucked cock before, but he was eager.

He bobbed back and forth, licking the underside, as he worked. Slowly he got used to Tsuna’s size and girth, relaxing his throat as he swallowed Tsuna down to the root. He moaned around the thick shaft.

Tsuna moaned, arching his back in pleasure. He could feel his release building, his own very large balls itching for release. The brunette tried to hold back, but the thread was tearing. When Fuuta started humming around his shaft he lost it. “Fuuta I’m cumming!” he cried out, hoping the boy would pull off, but no the boy pulled back to the head and started sucking harder, pumping his shaft. Tsuna erupted into his mouth, thick spurts of fresh man milk. It sprayed over his tongue, and it was like fireworks.

The boy saw stars his massive 17 incher sprayed his semen, and drenched Tsuna’s shirt and sheets. “Tsuna-ni,” the 10 years later brunette panted. He swallowed every drop Tsuna had to offer. “Tsuna-ni I want you inside me!”

“You what?!” he was surprised, despite being bigger he still wants to bottom. To prove his point Fuuta turned around and began stretching his hole. His hand was slick with pre, Tsuna’s pre, he wet his hole before plunging a finger inside. “Ahh Tsuna!” he moaned, he rocked on his finger making his big tool swing.

One finger, quickly became two, Fuuta scissoring himself open. Tsuna’s face was beat red, his cock twitching in excitement. ‘Oh man, oh man!’ he thinks, licking his lips. Fuuta ads a third finger and begins working his hole open. “Tsuna-ni I want you inside me.” he was panting so sexily.

Fuuta strokes his cock to collect more pre, and switches hands. His hole is glistening, getting worked as fingers twist and curl, working it for Tsuna. When he went to switch again, leaving his hole gaping and twitching, Tsuna couldn’t sit back anymore.

Tsuna gets behind Fuuta and positions his cock at the boy’s hole. He grips Fuuta’s plump cheeks. “Are you sure about this?”

“Yes please, fill me, I want you!” Fuuta pushes back, the head briefly slipping into the ring. Tsuna loses all control, and slams back into Fuuta’s willing body. “Yes!” he howled, his large cock shooting a spurt of cum. A mini orgasm rocked his body. He was so full so fast! His body shook with pleasure.

‘Fuuta was so aroused I slipped right in.’ Tsuna began to move thrusting into his tight channel. “Ohh Fuuta!” he moaned. “Tsuna!” his older partner gasped. 

Tsuna’s length brushed his prostate with every pass. His pleasure made his inner walls clench and squeeze. The friction was amazing, every inch was hugged as it thrust in and out of him. Without any touch to his cock Fuuta came hard, his seed erupted and formed a massive puddle in Tsuna’s bed.

In his climax, his hole clamped down on Tsuna’s dick, the smaller brunette couldn’t hold back. He gripped the male’s hips tight, buried balls deep rammed right against his sweet spot he came. Fuuta came again, as Tsuna’s seed pelted his prostate. The two shuddered in pleasure, their orgasms rocking them to their core.

To Tsuna’s surprise Fuuta was still horny. “Tsuna-ni...” he passed him the bottle of the pills. “Give these a shot.” Tsuna stared at them before popping one. He felt similar heat as to the dying will pills, but something was different.

“Ohhh!” His body started to age, his developing body springing forth. His muscles formed, getting thicker. His cum splattered shirt got tighter and tighter, before ripping apart. He was becoming his 10 year later self. The years being very good to him as he got ripped. He towered over Fuuta and that wasn’t the only thing that was growing.

Fuuta gasped feeling Tsuna’s penis getting thicker, stretching his hole wider. “Ahhh Tsuna!” he moaned. Not just girth, Tsuna’s dick was sinking deeper and deeper into Fuuta’s ass. By the time Tsuna was 20 inches long, Fuuta found himself cumming again. “Tsuna-ni so biiiig!” he howled on the last line in orgasm.

His stomach bulged, and Tsuna’ cock was still growing. Five more inches split the bottom brunette deeper. His eyes rolled up as another orgasm tore through him. His semen rolled over Tsuna’s bed like a waterfall. “Fuuta...” the male shivered. “I’m going to fuck you, prepare yourself.”

Nothing could prepare him for this, Tsuna’s massive rod pulled back till only the tip rested inside. Fuuta whined at the loss of the monster dick, never in his life did he think he could be so empty.

Tsuna thrust back in, and everything was good again. Fuuta howled, toes curling. His hands came to rest on the bulge in his stomach. ‘I feel it, Tsuna’s dick!’ he was seeing stars. The male’s thrusts were stronger than before.

He pulled them off his bed, standing up he kept Fuuta suspended on his dick, his toes barely touching the floor. He starts thrusting faster, making the now smaller 17 inch dick slap and bounced wildly. Fuuta howls, as his prostate was hammered to oblivion, every thrust wrecking and molding his channel into the perfect cock sleeve for Tsuna.

Fuuta’s balls shifted, shrinking as he has orgasm after orgasm. His floor, his desk, his wall all got covered in cum. Fuuta’s front was drenched, face, neck, pecs, his perky nipples, abs, crotch, and legs.

He chanted Tsuna’s name like a mantra, it was the only thing keeping his sanity. Not only was Tsuna massive, it seemed his stamina had made leaps and bounds. He plundered Fuuta’s hole for what felt like hours. His pre wet his insides, making sexy noises as he thrust in and out.

When he finally came, the force of his orgasm pushed Fuuta off his cock. Semen poured into his belly, filling him up to the brim, and with nowhere to go the semen built up and pushed Fuuta off his cock. His channel was flooded and his insides drenched. He eventually fell off Tsuna’s cock, and Tsuna’s dick continued to cum.

His ass, taint, legs, feet, back, hair and arms became drenched. He fell into a sea of their combined cum, a blissed out look on his face. His ass was left gaping, filled to the brim with seed.

Tsuna fell back on his bed, his cock still hard and aching. “Still horny Tsuna?”

“Reborn!” Tsuna gasped.

“Looks like got over your big dick shyness, who knew your future self was so hung.” he says. “It seems your still horny.” Reborn returned to his adult self. “Don’t worry I called your friend’s to help.” he opened the door where the Gokudera, Yamamoto, Ryohei, even Hibari were standing there dicks hard in their pants. “Get naked boys your boss needs release.”

Clothing was tossed aside, and Tsuna was in for a long night. The pills lasted for 10 hours, but every guardian was willing to chip in for their development.

It was a good thing the mafia cleanup crew didn’t ask many questions. Tsuna kept a steady supply of the new pills. Fuuta was later asked who was Tsuna’s number 1 lover, he may have cheated but he was the top of the list. Tsuna would never say for sure.

End


End file.
